Some fuel combusting engines may utilize two or more different fuels to provide performance benefits over a variety of different operating conditions. For example, some engines may include a fuel system that includes separate liquid and gaseous fuel injectors for each cylinder of the engine. Each of these fuel injectors may be driven by a corresponding electronic driver to cause fuel to be injected to the cylinder in response to the operating conditions of the engine.
The inventors herein have recognized a disadvantage of the above approach. Namely, the inventors herein have recognized that control circuitry and wiring utilized with a dual injector enabled engine may substantially increase the cost and complexity of the fuel system. To address these and other issues, the inventors herein have provided a fuel delivery system for an engine and a method of its operation, whereby a plurality of fuel injectors of a given cylinder may be driven via a common electronic driver while also enabling operation of only a selected one of the plurality of fuel injectors at a given instance.
As a non-limiting example, the fuel delivery system includes a first fuel injector configured to deliver a first fuel to a first cylinder of the engine; a second fuel injector configured to deliver a second fuel to the first cylinder of the engine; an electrical relay system disposed between a first electrical potential and each of the first fuel injector and the second fuel injector; an electronic driver disposed between a second electrical potential and each of the first fuel injector and the second fuel injector; and a control module. The control module may be configured to switch the electrical relay system to a first position to select the first fuel for delivery to the engine, where the first position electrically couples the first electrical potential to the first fuel injector; switch the electrical relay system to a second position to select the second fuel for delivery to the engine, where the second position electrically couples the first electrical potential to the second fuel injector; and close the electronic driver to deliver the selected one of the first fuel or the second fuel to the first cylinder via a respective one of the first fuel injector or the second fuel injector.
Furthermore, the inventors herein have provided several approaches for transitioning this fuel delivery system between a first mode where a first injector is operated to deliver fuel to the cylinder and a second mode where a second injector is operated to deliver fuel to the cylinder of the engine, while also maintaining a prescribed air-fuel ratio throughout the transition. As a non-limiting example, a transition between these two modes may be performed during a time period when none of the fuel injectors associated with the electrical relay system are performing a fuel injection. As another example, a transition between these two modes may be performed while a fuel injection is being performed by adjusting a fuel injection rate or fuel injection pulse-width of at least one of the two fuel injectors relative to the other fuel injector to reduce fueling errors that may otherwise occur as a result of the transition.